1. Field of the Invention
The present invention relates to a chain, and more particularly to a chain having multiple chain units. Each chain unit is composed of two outer plates, two inner plates and a pin securely connecting the outer plates to the inner plates. The inner plate has two hollow cones oppositely formed on two sides of the inner plate and two tubes each formed on a corresponding one of the hollow cones. A space between an inner face of the hollow cone and the tube is defined to receive therein oil. A rivet hole is defined to align with a pin hole in the outer plate. Therefore, after the outer plates and the inner plates are combined by the pin, the oil inside the chain unit is able to gradually flow out of the chain to lubricate the parts.
2. Description of Related Art
A conventional chain is composed of multiple chain units each having an inner plate provided with inner sleeves, an outer plate with outer sleeves each received in a corresponding one of the inner sleeves and pins provided to secure the engagement between the inner plate and the outer plate. In order to improve the smoothness of the chain, some manufacturers even add in a guiding plate to the chain unit so that when the chain is in use, the guiding plate is able to adapt to the sprocket of a bicycle to smoothen the operation. However, none of the improvements mentioned or introduced to the market does any thing to improve the lubrication between parts so as to prolong the life span of the chain.
To overcome the shortcomings, the present invention tends to provide an improved chain to smoothen the operation of the chain.
The primary objective of the present invention is to provide an improved chain having therein a space to receive oil so that when the chain is in operation, the oil will gradually seep out of the space to lubricate the outer plate and the pin.
Another objective of the invention is that a tube formed in an inner face of each hollow cone has an inclined top face relative to a top face of the inner plate so that when the oil seeps the oil flows to the lower portion in the inclined top face.
Still another objective of the invention is that the tube has multiple cutouts defined in a top face of the tube so that the oil is able to flow out of the space through the cutouts.